Ultraviolet-sensitive photographic element



Patented May 23, 1 944 Earle E. Richardson and Jonas John Chechak, Rochester, N. Y; assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application June 1, 1942,

Serial No. 445,388

10 Claims. (01. 95-7) This invention relates to a photographic element which is sensitive to the extreme ultraviolet portion (if the spectrum.

In modern industrial and scientific research, spectrophotography plays a considerable part, and in this field the characteristics of various materials under the influence of ultraviolet radiations are of interest. Much of this kind of work is now done with the quartz spectograph, and measurements are made from the visible as far to the ultravioletas possible. This work is, of course, done with the help of commercially obtainable photographic plates or films. The materials available have, however, introduced defects due largely to the fact that the gelatin, in which the silver halide grains of the emulsion are embedded, absorbs the radiations of very short wavelengths, thereby preventing their action upon the silver halide grains, which in themselves are sensitive to the radiations.

A number of previous workers have attempted to overcome this drawback by incorporating in the emulsion afluorescent substance. The purpose of such substances, in general, is to transform the radiationsof short waves to radiations of longer wavelengths, which are not so strongly absorbed by the gelatin. In this way, the short wavelength radiation is changed to longer wave length radiation, which is able to penetrate the gelatin and act upon the silver halide grains. These secondary radiations are usually of a blue or greenish color.

from the group consisting of dialkyl and trialkvl amines in which each alkyl group contains from Amethod of sensitizing to the ultraviolet, which has advantages over the older method of incorporating the fluorescent material in the emulsion, consists of overcoating the emulsion with a thin film comprising ethyl-dihydro-collidine-u dicarboxylate in order to bring about the necessary energy transformation. While the use of the collidine derivative necessitates no change in the developing and fixing procedure, it does require a wash with alcohol or a swabbing with cotton, while the element is in the developer. Other substances used in this connection may actually require removal by means of a suitable solvent before development of the photographic element. I

We have now found an ultraviolet sensitizing layer which is completely removed in the regular alkaline developers and requires no additional treatment of any kind. After development the plate or film can be fixed in the usual manner, washed and dried. The materials which we employ to provide sensitivity to the ultraviolet are his ammonium salts of aliphatic amines selected seven to twelve carbon atoms, and a his sulfonic acid of the following general formula:

no 0115 c0501:

wherein It represents a member selected from the tained from the his sulfonic acids containing.

acylamino groups are advantageously employed. These acylamino compounds are ordinarily crystalline substances which can be readily adapted to the practice of our invention. Typical examples of these bis ammonium salts are the his dioctylamine salts of 4,4'-diacetylamino-dibenzyl- 2,2'-'disulfonic acid; diacetyl-o-tolidine-2,2'-disulfonic acid and 4,4-diacetylamiho-stilbene- 2,2'-disulfonic acid.

To sensitize a photographic silver halide emulsion with our new ultraviolet sensitizers, the emulsion coated on a suitable support, such as a glass plate, is bathed for about thirty seconds in a 1% solution of the his ammonium salt in ethyl alcohol. Following bathing, the excess solution is allowed to drain oil and the photographic element is dried in a suitable position on adiying rack. I

Our invention, of course, is directed primarily to the customarily employed gelatino silver chloride, chlorobromide, bromide and bromiodide developing-out emulsions. However, it can also be practiced with silver halide emulsions in which the carrier for the silver halide is other than gelatin, e. g. a cellulose derivative or a resin.

In addition to the his ammonium salts recited above, wehave found that the following his ammonium salts are also efllcacious ultraviolet sensitizers; the dioctylamine salts of 2-acetylaminonaphthalene-6,8-disulfonic acids and l-acetylamino-naphthalene-6-sulfonic acid.

The bis ammonium salts which we employ in practicing our invention can be prepared as illustrated in the following example:

stilbene-2,2'.-disulfonic acid were dissolved in 600 cc. of water at C. The hot solution was filtered and then cooled to 25 C. To the cooled solution was added slowly with stirring a solution of 30 g. 01 dioctylamine in 50 cc. of glacial acetic acid, 200 cc. of ethyl alcohol and 200 cc. of water. A white precipitate formed. The resulting mix-.- ture was stirred for one hour. The precipitate was then filtered oil, washed with 500 cc. of cold water and pressed dry. The precipitate was dissolved in 500 cc. of boiling ethyl alcohol and the hot solution was filtered. The filtered solution was cooled somewhat and then poured slowly,

with stirring, into 800 cc. of cold water. The bis dioctylamine salt separated out as an oil which solidified and formed a powder after stirring for one hour. The resulting mixture was permitted to stand for several hours, after which the his dioctylamine salt was filtered oil and washed with 500 cc. of cold water. The salt was pressed to remove water and was finally dried on the steam bath. Yield 45 g.

The other bis ammonium salts which we employ in practicing our invention can be similarly prepared, making due allowance for the molecular weight of the starting materials employed.

4. Aphoto-sensitive silver halide emulsion containing a bis ammonium salt of an aliphatic amine and a his sulfonic acid of the followins general formula:

y Fr n SOIOH wherein n represents a positive integer of from one to two andR, represents an acylamino group,

What we claim as our invention and desire to be secured by.'Letters Patent of the United States is:

1. A photo-sensitive silver halide emulsion conamine and a bis sulfonic .acid general formula:

H0023 BOzOH s' )-iary V wherein n represents a positive integer of from one to two and R represents a member selected from the group consisting of amino, allwlamino and -acylamino groups and Z represents a divalent 'organic radical, said aliphatic amine being selected from the group consisting of dialkyl and trialkyl amines in which each alkyl group contains from 7 to 12 carbon atoms.

2. A photo-sensitive gelatino silver halide emulsion containing a his ammonium salt of an allphatic amine and a his sulfonic acid of the following general formula:

7 (Z) liq-cry] wherein n represents a positive integer of from one to two and R represents a member selected from the group consisting ofamino, alkylamino and acylamino groups and Z represents a divalent organic radical, said aliphatic amine being setaining a bis ammonium salt of an aliphatic of the following lected from the group consisting of dialkyl and.

trialkyl amines in which each alkyl group contains from! to 12 carbon atoms.

3. A photo-'senstive gelatino silver halide developing-out emulsion containing a bis ammonium salt of an aliphatic amine and a his sulfonic. acid of the following general formula:

wherein n represents a positive integer-of from one to two and R represents a member selected from the group consisting of amino, alkylamino and acylamino groups and Z represents a divalent organic radical, said aliphatic aminebeing selected from the group consisting of dialkyl and trialkyl amines in which each alkyl group contains from 7 to 12 carbon atoms.-,

and Z represents a divalent organic radical, said aliphatic amine being selected from the group consisting of dialkyl and trialkyl amines in which each alkyl group contains from 7 to 12 carbon atoms.

5. A photo-sensitive gelatino silver halide emulsion containing a bis ammonium salt of an aliphatic amine and a his sulfonic acid of the following general formula:

wherein n represents a positive integer of from one to two and R represents an acylamino group, and Z represents a divalent organic radical, said aliphatic amine being selected from the group consisting of dialkyl and trialkyl amines in which each alkyl group contains from 7 to 12 carbon atoms.

6. A photo-sensitive geiatino silver halide developing-out emulsion containing a his ammonium salt of an aliphatic amine and a his sulionic acid of the following general formula:

niuinsalt of a dioctyl amine and 4,4"-diacetylamino-dibenzyb-ZW-ditulfonic acid.

9. A photo-sensitive gelatino silver halide developing-out emulsion containing a his ammonium salt of a dioctyl amine and. 4,4'.-diacetyl amino-diphenyl urea-3.3'-disulfonic acid.

. 10. A photo-sensitive gelatino'silver halide developing-out emulsion containing a his ammonium salt of a dialkyl amine and a his sulfonic acid oi. the following general formula:

wherein R. represents an acylamino group and Z represents a divalent organic radical, said dialkyl amine containing from 7 to 12 carbon atoms in each alkyl group. I

I EARL-E E. RICHARDSON. JONAS JOHN CHECHAK. 

